Such illumination systems are known per se. They are used, inter alia, for general lighting purposes, such as spot lights, flood lights and for large-area direct-view light-emitting panels applied, for instance, in signage, contour lighting, and billboards. Furthermore, the illumination systems are used as task light.
Generally, such illumination systems comprise a multiplicity of light sources, for instance, light-emitting diodes (LEDs). LEDs may be light sources of distinct primary colors, such as, for example, the well-known red (R), green (G), or blue (B) light emitters. In addition, the light emitter may have, for example, amber (A), magenta or cyan as primary colors. These primary colors may be either generated directly by the light-emitting diode chip, or by a phosphor upon irradiance with light of a shorter wavelength (e.g. green, blue or UV-light) from the light-emitting diode chip. In the latter case, also the use of mixed colors or white light is possible as one of the primary colors. Generally, the light emitted by the individual light sources is mixed so as to obtain a uniform distribution of the light while eliminating the correlation of the light emitted by the illumination system with a specific light source.
U.S. Pat. No. 6,502,956 discloses an illumination system including a housing, a circuit board mounted to the housing, an electric connector attached to the housing and electrically connected to the circuit board, a plurality of light-emitting diodes (LEDs) mounted to the circuit board that are activated to emit a light output when an electric voltage is applied to the electric connector, and a plurality of LED covers each mounted to cover one of the plurality of LEDs. Each LED cover includes a lens portion that redirects the light output from the one LED, and a side portion that attaches to either the PCB or the LED to secure the LED cover in place. The LED covers may be individually movable or can be replaced so as to modify the overall distribution pattern of the LED lamp.
The known illumination system has the drawback that the illumination system has a relatively complicated construction.